Hi there, Welcome to HCM, Multivitamins and minerals like iron and calcium and protein supplements are routinely prescribed in pregnancy. We advise folic acid 400 micrograms from 3 months prior to conception to 12 weeks of pregnancy to avoid neural tube defects. The iron is advised after 20 weeks especially if the women is anemic (hemoglobin less than 11 gm/dl). What you need to known is only a certain amount of iron can get absorbed each day and even if you take excess it will not be absorbed but can increase the side effects, like constipation and gastric upset. Also iron tablets are often difficult to take by some women. The number of months you need to take depends on your hemoglobin levels. Also calcium is advised after 20 weeks as that s the period when bone formation of the baby starts and this extra calcium is needed. Do remember not to take the iron and calcium together as they can interact with each other and decrease each others absorption. So do not be concern, take whichever iron preparation suits you best and take it at a different time from the calcium. The 100 mg iron should be more than adequate. Hope this helps. Regards.